Two adults were last night tested for bird flu after Welsh authorities confirmed an outbreak on a remote smallholding in north Wales. However, they reassured the public that this was not the H5N1 strain, which is potentially deadly to humans and which resulted in 160,000 turkeys being slaughtered this year in Norfolk.

Police cordoned off the road about a mile from the farmhouse in Llanfihangel Glyn Myfyr, near Corwen, Denbighshire. It is understood that all the 45 chickens and two geese on the farm were slaughtered and everyone entering the site was offered the drug Tamiflu as a precaution.

The National Public Health Service for Wales said two people living on the farm had symptoms of flu and conjunctivitis. Both are receiving treatment and have had blood tests. Neither is in hospital.

Christianne Glossop, chief veterinary officer in Wales, said the strain was H7N2 low pathogenic avian influenza which is deadly to poultry, but usually only provokes mild symptoms in people. It caused the destruction of more than 4.7 million chickens and turkeys in the US in 2002.

Speaking at the Welsh assembly in Cardiff, Dr Glossop said that chickens had been dying at the smallholding over the past two weeks. Fifteen 22-week-old Rhode Island Red chickens had been bought by the owners a fortnight ago, bringing their total number of birds to 45 chickens and two geese.

It appeared last night that the disease could have been brought on to the small holding after Dr Glossop confirmed that one of the birds died the day after they were taken to the site.

Dr Glossop said: "At that time there was no reason to suspect notifiable avian disease. We have no reason to believe that the viral infection is spreading rapidly within this small population. This isn't another East Anglia at the moment.

"We do not anticipate this virus transmogrifying into the H5 strain, but it's not impossible. This strain pretty unusual. We don't know how it's going to develop."

Wendy Barclay, chair in influenza virology at Imperial College London, said: "Most influenza viruses that infect birds are the 'low pathogenicity' type. These viruses cause mild symptoms in poultry, and do not transmit to humans."

Investigations are being carried out to determine where the birds were purchased from.